Palladium(0) π-Lewis Base Catalysis: Concept and Development

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(10), С. 6422 - 6437

Опубликована: Март 1, 2024

The development of a new catalytic strategy plays vital role in modern organic chemistry since it permits bond formation an unprecedented and more efficient manner. Although the application preformed metal complexes as π-base-activated reagents have enabled diverse transformations elegantly, concept by directly utilizing transition metals π-Lewis base catalysts remain underdeveloped, especially field asymmetric catalysis. Here, we outline our perspective on discovery palladium(0) catalyst, which is capable increasing highest occupied molecular orbital (HOMO) energy both electron-neutral electron-deficient 1,3-dienes 1,3-enynes upon flexible η2-complexes formed situ resultant π-backdonation. Thus, fruitful carbon–carbon-forming reactions with electrophiles can be achieved enantioselectively vinylogous addition pattern, conceptually different from classical oxidative cyclization mechanism. Emphasis will given to mechanism elucidation, features, reaction design together further this emerging field.

Язык: Английский

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Enantioselective Cross-[4 + 2]-Cycloaddition/Decarboxylation of 2-Pyrones by Cooperative Catalysis of the Pd(0)/NHC Complex and Chiral Phosphoric Acid

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(10), С. 6936 - 6946

Опубликована: Фев. 28, 2024

Here, we describe a cooperative Pd(0)/chiral phosphoric acid catalytic system that allows us to realize the first chemo-, regio-, and enantioselective sequential cross-[4 + 2]-cycloaddition/decarboxylation reaction between 2-pyrones unactivated acyclic 1,3-dienes. The key success of this transformation is utilization an achiral N-heterocyclic carbene (NHC) as ligand newly developed chiral cocatalyst. Experimental investigations computational studies support idea Pd(0)/NHC complex acts π-Lewis base increase nucleophilicity 1,3-dienes via η2 coordination, while simultaneously increases electrophilicity by hydrogen bonding. By synergistic catalysis, 2]-cycloaddition decarboxylation proceeds efficiently, enabling preparation wide range vinyl-substituted 1,3-cyclohexadienes in good yields enantioselectivities. synthetic utility demonstrated transformations product various valuable six-membered carbocycles.

Язык: Английский

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Palladium(0) and Brønsted Acid Co‐catalyzed Enantioselective Hydro‐Cyclization of 2,4‐Dienyl Hydrazones and Oximes

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(44)

Опубликована: Авг. 6, 2024

Abstract The transition metal‐catalyzed asymmetric hydro‐functionalization of 1,3‐dienes has been well explored, but most reactions focus on electron‐neutral substrates in an intermolecular manner. Here we first demonstrate that readily available 2,4‐dienyl hydrazones and oximes can be efficiently utilized the hydro‐cyclization reaction under co‐catalysis a Brønsted acid chiral palladium complex, furnishing multifunctional dihydropyrazones dihydroisoxazoles, respectively. Diverse substitution patterns for both types electron‐deficient diene compounds are tolerated, corresponding heterocycles were generally constructed with moderate to excellent enantioselectivity, which elaborated access products higher molecular complexity diversity. Control experiments density functional theory calculations support α‐regioselective protonation dienyl by concurrent π‐Lewis base activation Pd 0 complex is energetically favoured formation active π‐allylpalladium intermediates, outer‐sphere allylic amination or etherification mode adopted deliver observed cyclized enantioselectively.

Язык: Английский

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HFIP-Promoted Regioselective Hydrofunctionalization of Enamides and N-Vinyl Azoles

The Journal of Organic Chemistry, Год журнала: 2025, Номер unknown

Опубликована: Апрель 29, 2025

An efficient and regioselective method for the intermolecular hydrofunctionalization of enamides N-vinyl azoles has been developed, enabling formation diverse C-S, C-O, C-N, C-C bonds. This transition-metal-free, additive-free, Brønsted acid-free protocol employs hexafluoroisopropanol (HFIP) as sole reagent, which plays a dual role: iminium carbocation intermediate facilitating nucleophile generation through its hydrogen-bonding network. The reaction demonstrates exceptional substrate versatility, accommodating thiophenols, alcohols, heterocyclic amines, well NH-free indoles, pyrroles, carbazoles nucleophiles, proceeding via Markovnikov-selective pathway. is general simple with broad compatibility.

Язык: Английский

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Theoretical Insight into the Palladium-Catalyzed Prenylation and Geranylation of Oxindoles with Isoprene

Inorganic Chemistry, Год журнала: 2024, Номер 63(11), С. 4855 - 4866

Опубликована: Март 6, 2024

This work presents a comprehensive mechanistic study of the ligand-controlled palladium-catalyzed prenylation (with C5 added) and geranylation C10 reactions oxindole with isoprene. The calculated results indicate that bis-phosphine ligand monophosphine fundamentally share common mechanism. mechanism involves formation two crucial species: η3-allyl-Pd(II) cation an carbon anion. Furthermore, necessitate assistance second molecule, which serves as Brønsted acid, providing proton to generate nitrogen anion then acts base, abstracting C–H from another molecule form These details differ significantly those proposed in experimental work. present calculations do not support presence Pd–H species η3, η3-diallyl-Pd(II) intermediate, were previously suggested experiments. theoretical rationalize finding favors oxindole, while enables oxindole.

Язык: Английский

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Asymmetric Construction of Multifunctional γ-Lactams from 1,3-Dienes and α-Ketoamides via Pd(0)-π-Lewis Base Catalysis

Organic Letters, Год журнала: 2023, Номер 25(36), С. 6649 - 6653

Опубликована: Сен. 1, 2023

A straightforward approach for the asymmetric synthesis of multifunctionalized γ-lactams, including those bearing two tetrasubstituted stereogenic centers, has been developed through a palladium-catalyzed vinylogous addition/allylic amination process between 1,3-dienes and α-ketoamides. This protocol features advantages ready substrate availability, broad applicability, high efficiency, excellent stereoselectivity, making it an attractive complementary tool to previous strategies.

Язык: Английский

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Switchable Chemo‐, Regio‐ and Pseudo‐Stereodivergence in Palladium‐Catalyzed Cycloaddition of Allenes

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(45)

Опубликована: Июль 11, 2024

Here, we report a strategy enabling triple switchable chemo-, regio-, and stereodivergence in newly developed palladium-catalyzed cycloadditions of allenes. An asymmetric pseudo-stereodivergent cycloaddition allenes bearing primary leaving group at the α-position, where dynamic kinetic hydroalkoxylation racemic unactivated was enantio-determining step, is realized, providing four stereoisomers [(Z,R), (Z,S), (E,S), (E,R)] containing di-substituted alkene scaffold stereogenic center. By tuning reaction conditions, mechanistically distinctive uncovered selectively with same set substrates. switching position allenes, involving an intermolecular O-attack disclosed. Diverse mechanisms reactions enable rapid access to structurally stereochemically diverse 3,4-dihydro-2H-1,4-benzoxazines high efficiency selectivity.

Язык: Английский

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Rapid Construction of Hexahydro‐1H‐pyrrolo[3,2‐c]pyridines with Functionalized 1,3‐Enynes and Imines via Palladium Catalysis

Asian Journal of Organic Chemistry, Год журнала: 2023, Номер 12(6)

Опубликована: Май 18, 2023

Abstract Presented herein is a palladium catalyzed tandem reaction between 3‐aminoethyl group tethered 1,3‐enynes and imines, proceeding through cascade vinylogous addition/reductive elimination/protonation/allylic amination 1,3‐hydrogen transfer sequence. A collection of complex hexahydro‐1 H ‐pyrrolo[3,2‐ c ]pyridine architectures were straightforwardly constructed in moderate yields diastereoselectivity.

Язык: Английский

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Theoretical study of Ni(0)-catalyzed intermolecular hydroamination of branched 1,3-dienes: reaction mechanism, regioselectivity, enantioselectivity, and prediction of the ligand

Journal of Molecular Modeling, Год журнала: 2024, Номер 31(1)

Опубликована: Дек. 11, 2024

Язык: Английский

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Switchable Chemo‐, Regio‐ and Pseudo‐Stereodivergence in Palladium‐Catalyzed Cycloaddition of Allenes

Angewandte Chemie, Год журнала: 2024, Номер 136(45)

Опубликована: Июль 11, 2024

Abstract Here, we report a strategy enabling triple switchable chemo‐, regio‐, and stereodivergence in newly developed palladium‐catalyzed cycloadditions of allenes. An asymmetric pseudo‐stereodivergent cycloaddition allenes bearing primary leaving group at the α ‐position, where dynamic kinetic hydroalkoxylation racemic unactivated was enantio‐determining step, is realized, providing four stereoisomers [( Z,R ), ( Z,S E,S E,R )] containing di‐substituted alkene scaffold stereogenic center. By tuning reaction conditions, mechanistically distinctive uncovered selectively with same set substrates. switching position allenes, involving an intermolecular O‐attack disclosed. Diverse mechanisms reactions enable rapid access to structurally stereochemically diverse 3,4‐dihydro‐2 H ‐1,4‐benzoxazines high efficiency selectivity.

Язык: Английский

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